It is well known that plastics are the product of the petrochemical industry and obtained from non-renewable petroleum resources. Plastic products have been applied in domestic economic fields, such as automobiles, household electrical appliances and articles of daily use, and they are essential to society.
However, petroleum leads to environmental deterioration, greenhouse gas effect and white pollution whilst providing considerable organic raw materials and energy. As the use of petroleum for development is at the expense of environmental destruction and the availability of petroleum resources is limited, it is urgent to cast off petroleum.
Meanwhile, a great deal of stone exists in the natural world and especially many stones that are produced as biproducts during the isolation of various mineral resources. Such stones are required to be excavated and processed in advance, with high consumption of labour and material resources. But excavated stones cannot be utilized and can only be disposed of as waste, which has an impact on the environment.
At present, these stones are sometimes used as the raw materials for making bathroom fittings and a relatively well-developed molding method of manufacture is conducted with a casting shaking method. Take the production of a basin using the casting shaking method for instance. The technological process is mixing, casting, shaking, curing, follow-up processing and surface treatment. For mixing, various additives are mixed in different proportions to make them uniform, and during the casting process, mixed materials are cast in molds and shaken to compact them in the molds. During curing, the cast molds are kept for 30-60 minutes and raw materials are solidified for shaping, while the follow-up processing is to open the molds and conduct a trimming process of the products. Finally, coating is sprayed on the outer surface of the products to finish the surface treatment.
The method for making the products with stones is a complex production process with low acceptance rate of the products, extremely low production efficiency, high production cost and difficulty in mass production. The amount of stones consumed is quite limited. Such use of stones cannot completely use up the existing stones nor replace plastics at a large scale.
With the forgoing method for producing products with stones, the products obtained have poor and unstable quality. The method cannot be applied to produce products with high quality and the low-class products obtained can only be used in cases where high quality products are not required.
Restricted by compacting methods and molds, methods for making products with stones are difficult, especially when the products have a complex structure and special surface treatment, or precise parts such as automobile components or electrical units.
Until now, people considered that only the shaking casting method can be used for making products with stones, hence it is still in the lag phase without advancement. Therefore, to develop a new stone molding technology for replacing plastics has both practical significance and great economic value.